A question about past evolution on earth

[EmoBorg]

Our planet earth is around 4 to 5 billions years old. The earliest life forms evolved in the first billion years of earth's existence. We modern humans appeared around 100 000 to 200 000 years ago. We went from caveman to spaceman in that short period.

Considering earth's age. Could it have been possible for sentience to have manifested itself in another species that once existed earlier perhaps millions or billions years ago on our planet. I am not just talking about a space faring species like the dinosaur race featured in the VOY episode" Distant Origins" but a sentient species that achieved the technology level of either stone, bronze or iron age technology before meeting it's end due to environmental changes, tectonic plate movements or disease.

To sum up my question, are we sure that we are the first sentient species to evolve on earth considering how old earth is and how early in earth's history, life appeared.

 

[Robert Maxwell]

What you're talking about are two different things: sentience and technology. One can be sentient without having technology. Dolphins, for instance, are considered sentient but they have no ability to make tools or develop technology, thanks to lacking appropriate limbs for it.

So, it's possible that past species were sentient in ways that we would recognize, but we have no evidence that other species were able to develop technology as we know it.

 

[Christopher]

A technological civilization would leave a detectable trace in the geological record. It would alter the atmosphere in ways that would show up in mineral strata from the era. It would domesticate plants and animals or bring about an exchange of organisms between widely separated regions, leaving evidence of its influence in the evolutionary record. It would leave artifacts that could survive in the ground to the present day, such as fossilized wooden structures, or glass and ceramic, which are chemically similar to fossils and just as capable of surviving. Skeletal remains would show marks from weapons or medical tools. Fossil matrices might show evidence of clothing patterns impressed into the rock just as they reveal skin, scale, or feather patterns. If a past technological civilization had existed, we would almost certainly know about it.

As for sentience, that's a tricky question. Sentience simply means awareness and conscious perception, and it's increasingly evident that we are not the first or only sentient species on the planet by a long shot. Many animals, such as dolphins, whales, great apes, elephants, cephalopods, and birds, have been found to possess sophisticated intelligence or language ability comparable in some ways to human abilities. Recent brain scans of dogs suggest they may have a conscious awareness comparable to that of a 2- or 3-year-old human child, and if they do, then other higher mammals may as well. The preponderance of evidence is building that, far from there being a sharp dividing line between sentience and nonsentience, it's actually a wide continuum, with many different species having some level of sentience and intelligence. So it follows that many past species may have had a similar childlike level of consciousness and intelligence. If birds have a capacity for thought, it suggests that other dinosaurs may have as well.

But as for the particular level of sentience, intelligence, linguistic and symbolic sophistication, civilization, and tool use which modern humans have achieved, there's no evidence for any such thing in Earth's past.

 

[EmoBorg]

But as for the particular level of sentience, intelligence, linguistic and symbolic sophistication, civilization, and tool use which modern humans have achieved, there's no evidence for any such thing in Earth's past.

No evidence yet. I mean we are just finding out that there were several different type of human species that lived on earth
50 000 years. We did not know about Homo floresiensis, Denisovans and Neanderthals until recent times. There might be more extinct human species waiting to be discovered.

It is hard believe that in the 4 to 5 billion years of earth's existence, humans are the only intelligence and sentient beings to appear on earth and that was in the last 100 000 years.

 

[Robert Maxwell]

I feel like you didn't even read our responses because you basically just said, "I don't believe you so I'm going to reiterate my original point." What do you even want to discuss, then?

 

[Christopher]

No evidence yet. I mean we are just finding out that there were several different type of human species that lived on earth
50 000 years. We did not know about Homo floresiensis, Denisovans and Neanderthals until recent times. There might be more extinct human species waiting to be discovered.

As I said, the effects of a technological civilization would be global. Most people don't realize just how profoundly human civilization has transformed this planet. The changes in the atmosphere as a result of the Industrial Revolution will leave an unmistakeable signature in the geological record for the rest of time. And we had a major global impact on the environment well before then. The Columbian Exchange, the transfer of plant and animal species (and diseases) all over the world as a result of regular contact between Eurasia/Africa and the Americas following 1492, has radically transformed biospheres and caused many extinctions. Future paleontologists could determine that there was no way for those species to move so extensively over such a short span of time except through regular maritime trade by a technological civilization. In the millennia before that, we transformed many species to suit our needs, and the fossil record would thus show evidence of many species acquiring traits that provided no evolutionary benefit for them, and all within a very short span of time, leading to the conclusion that they were altered to benefit some other species.

We've just made too many global changes that would be impossible to miss. Even if we disappeared tomorrow, every future intelligent species that evolves on or explores this planet in the hundreds of millions of years to come would be able to tell very easily that we were here. And by the same token, if any technological civilization had arisen in the distant past, it would also have had influences that could be detected globally. We would know by now.

It is hard believe that in the 4 to 5 billion years of earth's existence, humans are the only intelligence and sentient beings to appear on earth and that was in the last 100 000 years.

The flaw in that argument is that for most of that span, the only life on Earth was unicellular. Multicellular life didn't begin to emerge until 450 million years ago, and it had many different hurdles to surmount from that point on -- evolving brains and nervous systems, evolving skeletons, evolving lungs and legs, inventing endothermy, etc. There were a lot of different ingredients that had to be accreted gradually, one innovation at a time -- not just physically, but neurologically, as new parts of the brain were gradually added as new classes of life came along. And since evolution is not a targeted process, merely a succession of random mutations selected for or against by shifting environmental conditions, it often took tens of millions of years before a new innovation was added.

So for most of that 450 million years, brains and behaviors simply wouldn't have been complex enough yet for intelligence to occur. It took a lot of time for enough ingredients to be added to allow sufficiently complex mental activity. Of vertebrate species, only mammals (originating c. 225 million years ago) and birds (c. 150 m.y. ago) have been shown to have higher cognition. And neither mammals nor birds had the chance to amount to much until c. 65 m.y. ago when the non-avian dinosaurs died out and cleared the field for the new guys to take over. So the starting point is immensely more recent than your "4 to 5 billion years."

Besides, again, evolution has no particular direction. Human-level intelligence isn't something that was destined or required to happen. Countless species have managed just fine without it. True, increased intelligence does lend evolutionary advantages in a lot of cases, but it can have drawbacks too, such as the greater metabolic demand of a large brain. So the conditions have to be just right to promote it and justify its selection. Thus it took time.

Again, though, you're making the mistake of equating human-style language, technology, and civilization with intelligence and sentience. Intelligence has arisen several times already on Earth -- in birds, in great apes, in cetaceans, in elephants, in cephalopods. Some of those might be comparable to our own level, or at least to the level of a human chld. And sentience, an awareness of self and an ability to feel, is likely possessed by many more species still.

 

[EmoBorg]

I feel like you didn't even read our responses because you basically just said, "I don't believe you so I'm going to reiterate my original point." What do you even want to discuss, then?

I did read your post . But I don't know whether dolphins are sentient. They are intelligent but so are certain breeds of dogs. I do not consider dolphins sentient. Are dolphins able to recognize themselves when they see their reflection in the mirror? I know that the Apes can.

 

[sojourner]

Are dolphins able to recognize themselves when they see their reflection in the mirror?

Yes.
[yt]http://www.youtube.com/watch?v=WgJl4bONOqc[/yt]

 

[YellowSubmarine]

A technological civilization would leave a detectable trace in the geological record.

A wide-scale civilization, yes. But what about the evidence of limited tool use in a small region of the world? Couldn't it have disappeared in the course of a hundred million years, or at least have remained undiscovered until now?

Science is still discovering known species living next to human settlements, I wouldn't be that surprised if scientists missed one island of pot-making dinosaurs that went extinct a hundred million years ago (even if I would be much surprised if it does exist). The vast number of species that lived on the planet left no fossils behind, to think that something larger than that could have eluded us is enough of a possibility to give me pleasant sensation when I think about what we don't know. It's a bit of a pointless mind pleasure though, as alien civilizations are both more intriguing and more likely. Even paleocontact is more likely than pot-making dinosaurs, and that removes any excitement from the latter.

But the point remains – as you travel back in time or further away from Earth, the amount of little things that we don't know increases, and the chance for a big thing we don't know increases with them. Less so with our past, but still. There's also Mars that is relative to Earth is quite unexplored, leaving its past as mysterious as you can have it.
--

Actually, if tool use was enough, it's certain that there was a civilization before the humans. Not only many of the other great apes are also using tools today, we know that so did the Neanderthals, and our new enigmatic ancestor. So did Homo erectus and Homo ergaster, and both of them lived millions of years before we appeared. They were sentient, tool-using and you could say civilised. And Homo erectus might not even be an ancestor of ours.

And I wouldn't discount the Kentriodons either.

 

[JarodRussell]

Would we still be able to find geological evidence for a civilization that existed 60 million years ago? City ruins would be long gone, any environmental effects couldn't be distinguished from natural causes, and so forth, wouldn't it?

 

[YellowSubmarine]

Would we still be able to find geological evidence for a civilization that existed 60 million years ago? City ruins would be long gone, any environmental effects couldn't be distinguished from natural causes, and so forth, wouldn't it?

Exactly my point.

However, technological advancement is systematic in nature, it tends to spread, and it needs the already spreading technological advancements to make its steps forward. And while time erases evidence, some evidence always escapes its destructive power, so if there was a lot of it... We'd know about it.

So the technology we are talking about needs to be easily destroyed by time, difficult to spot by us and/or very localised (which also means primitive). You can't even get to pot making with such limitations I should think.

 

[JarodRussell]

I think that over such a great timespan even something as prominent as New York City would vanish without any traces.

 

[Christopher]

I did read your post . But I don't know whether dolphins are sentient. They are intelligent but so are certain breeds of dogs. I do not consider dolphins sentient. Are dolphins able to recognize themselves when they see their reflection in the mirror? I know that the Apes can.

I think you're misusing the word "sentient." Which is understandable, since most science fiction misuses it too. As I've been saying, sentience just means awareness and the ability to feel emotion, pleasure, or pain. True, for centuries we've egocentrically assumed that ability was unique to us and that animals were some kind of biological machines that we could abuse and slaughter at our convenience, but modern science is building up increasing evidence that we've been tragically wrong about that, that sentience is a far more common trait among animals than we have arrogantly assumed.

A technological civilization would leave a detectable trace in the geological record.

A wide-scale civilization, yes. But what about the evidence of limited tool use in a small region of the world? Couldn't it have disappeared in the course of a hundred million years, or at least have remained undiscovered until now?

Perhaps, but the anatomical and neurological adaptations that would permit such things wouldn't exist in a vacuum. There'd need to be a whole line of evolutionary stages leading up to it, and any species with manipulative capability, stereoscopic vision, advanced brains, and other traits necessary for tool use would have ancestral and related species with at least some of the same traits. And it's unlikely they'd all be so narrowly concentrated in territory as to have been completely effaced from the fossil record. After all, if they were capable of tool use, it's likely they would've used that advantage to expand their territory. And if they were intelligent enough to imagine and invent tools, they'd have the urge to see what lay over the horizon and find out whether it would benefit them.

Not to mention the time scales involved. From our perspective it seems like forever since our prehistoric ancestors harnessed fire or began horticulture, but in geological terms it was a short while ago. The odds that an earlier species got to the point of stone-age technology but died out before it spread widely around the world are very slim, simply because the interval between those events would be so brief.

It's increasingly reasonable to believe that sentience and intelligence exist in numerous evolutionary lines. But which of them have manipulative capability? True, we have seen a limited degree of tool use in birds and cetaceans, repurposing found objects into implements (birds build nests, dolphins use shells to trap fish). Elephants use branches as grooming tools and rocks to sabotage electric fences. Octopus repurpose shells into shelters. But none of them have the dexterity necessary to create tools, to do anything like weaving textiles or chiseling stone or baking pottery or smelting metal. Okay, cephalopods can be extremely dexterous, but good luck lighting a fire underwater.

I'm open to the possibility that we might find some evidence of undocumented giant-squid tool use or civilization once we dive deep enough into their largely unknown territory. But it's very unlikely that a prior technological species existed on land.

But the point remains – as you travel back in time or further away from Earth, the amount of little things that we don't know increases, and the chance for a big thing we don't know increases with them. Less so with our past, but still.

Yes, but the farther back you go, the fewer of the necessary evolutionary breakthroughs that contributed to intelligence would have existed yet. The odds get lower the earlier you go.

There's also Mars that is relative to Earth is quite unexplored, leaving its past as mysterious as you can have it.

Not really. We know enough about Mars to know that it could never have had anything more than unicellular life on or near its surface. There's a huge difference between "We don't know everything" and "We know nothing so we can pretend any crazy BS is equally likely." Even limited knowledge can rule out many possibilities.

Actually, if tool use was enough, it's certain that there was a civilization before the humans. Not only many of the other great apes are also using tools today, we know that so did the Neanderthals, and our new enigmatic ancestor. So did Homo erectus and Homo ergaster, and both of them lived millions of years before we appeared. They were sentient, tool-using and you could say civilised. And Homo erectus might not even be an ancestor of ours.

That's not what "civilization" means, though. A civilization is a state-based polity, an organized society with a subsistence method such as agriculture that allows a large, ordered population to coexist. It's one particular category of social and political organization.

 

[Gov Kodos]

I feel like you didn't even read our responses because you basically just said, "I don't believe you so I'm going to reiterate my original point." What do you even want to discuss, then?

Dude, the Great Old Ones created protohumans like Lucy as a slave force. When they left Earth for the stars, they abandoned their slave race which eventually evolved into humanity. Those early human who found some of the Great Old Ones technology founded the empire of Atlantis, but their greed, corruption, and ignorance of the full potential of that power led to the destruction of Atlantis. The scattered remains of that disaster have echoed through history in the tales of Homer and Troy, Babylon and Gilgamesh, Egypt and Osiris. The Templar Knights discovered some of the few remains of that long story and were silenced by the Church which is trying to suppress the ancient knowledge ever coming to light again.

 

[publiusr]

Now if an alien had landed and established a small outpost, the track record of its existance would exist off world, in that a small settlement wouldn't leave much of the way in terms of evidence here--which is bad in that a fossil transistor radio is what you need to find in order to prove aliens were ever here. So if we find fossil transistors, then it would have to be alien.

The idea is this. Alien pollutes its own planet--leaves during a Red Giant phase, etc.

Earth isn't quite as nice as what they left, they die soon without much of a foothold.

The evidence they exist is buried, and perhaps destroyed by geologic processes over deep time, and is next to impossible to find--and the small colony wasn't much to begin with.

 

[scotpens]

I did read your post . But I don't know whether dolphins are sentient. They are intelligent but so are certain breeds of dogs. I do not consider dolphins sentient. Are dolphins able to recognize themselves when they see their reflection in the mirror? I know that the Apes can.

I think you're misusing the word "sentient." Which is understandable, since most science fiction misuses it too. As I've been saying, sentience just means awareness and the ability to feel emotion, pleasure, or pain.

Yes, sentience (self-awareness, perception of one's environment, and the capacity for sensations such as pain and pleasure) is often confused with sapience (the ability to reason and to apply knowledge).

 

[USS Triumphant]

A technological civilization would leave a detectable trace in the geological record.

It would, yes, but I have to admit to wondering the same thing as the OP, and wondering whether or not we've actually SEEN those traces but then proceeded to come (temporarily, hopefully) to erroneous conclusions about where those traces came from and what they mean. Science can and has sometimes been wrong until further data is added to the pot of knowledge to work with.

 

[Pavonis]

There's probably been a lot of brain power in the oceans, but not much they could do with it - no fires, no metallurgy, etc etc etc.

Besides, is our level of intelligence really that useful for most species? Is our intelligence just a runaway feedback loop that created something interesting but not necessarily good for us in the long run, like a sabertooth's canines, or a peacock's tail?

 

[sojourner]

Sabertooth canines are apparently of some use since they have been demonstrated to evolve repeatedly in past species.

 

[gturner]

Well, scientists have just discovered why dolphins haven't developed sophisticated technology. It seems they instead float about, using puffer fish to get high.

news link

"After chewing the puffer and gently passing it round, they began acting most peculiarly, hanging around with their noses at the surface as if fascinated by their own reflection."

And we thought sea turtles were bad for drug use.